Exercise machines including a weight stack wherein an amount of weight applied to an attached cable may be selected by a user have been very popular. Such exercise machines may provide various selectable amounts of resistance, and thus may accommodate various exercises and various users with a single machine. There have been shortcomings, however, with conventional exercise machines that include a weight stack.
One problem with conventional exercise machines that include a weight stack lies in the way that weight is selected. Typically, a stem includes a plurality of apertures, each aperture corresponding to an aperture through a respective weight plate. To select a desired weight, a pin is inserted through an aperture of a weight plate and a corresponding aperture in the stem, thus coupling the weight plate to the stem. These pins may become misplaced, which may render the machine unusable. Additionally, misplaced, damaged, or stolen pins may be replaced with a pin that is of insufficient strength or size.
Another difficulty is that the insertion and/or removal of a weight selector pin may be difficult for some users. For example, the apertures in the stem and weights may become misaligned, making it difficult to insert and/or remove the weight selector pin.
U.S. Pat. No. 8,047,970 to Nalley teaches a weight plate with a detachable locking cartridge. Each weight plate in a weight stack may include such a detachable locking cartridge that includes a toggle switch that controls the displacement of a locking pin. Accordingly, a toggle switch may be rotated to position a pin into an aperture of a lifting pin. The locking cartridge of Nalley, however, has many shortcomings. For example, the locking cartridge is attached to the face of each weight. Since the pin, toggle switch, and associated linkages occupy significant space, the locking cartridges extend, cantilevered, a significant distance from the face of each weight. Accordingly, the locking cartridges may be susceptible to damage. Furthermore, each of the detachable locking cartridges and pins are separate from the lifting pin, being mounted to the weights, and do not provide weight selecting features that remain coupled to the lifting pin.
In view of the foregoing, improved devices and methods for weight selection would be desirable.